Northeast Regional Operational Workshop
Albany, New York
(click on
talk to view abstract)
Tuesday, November 5, 2002
8:15 am
Welcoming Remarks
Eugene P. Auciello, Meteorologist in Charge, NWS, Albany, New York
Warren R. Snyder, Science & Operations Officer, NWS, Albany, New York
Session A. CSTAR Projects
Session Chair - Kenneth D. LaPenta
8:25 am
Remarks by Session Chair
8:30 am
Precipitation Associated with 500 hpa Closed Cyclones: A Fifty Year
Climatology
Anantha R. Aiyyer
Department of Earth and Atmospheric Sciences, University at Albany, State
University of New York, Albany, New York
9:00 am
Anticipating Mesoscale Band Formation in Winter Storms
David R. Novak
NOAA/NWS, National Weather Service Eastern Region, Scientific Services
Division, Bohemia, New York
9:30 am
A Compare and Contrast Study of Two Banded Heavy Snow Events
Michael S. Evans
NOAA/NWS, Weather Forecast Office, Johnson City, New York
10:00 am
Break
10:30 am
Cutoff Cyclones: A Global and Regional Climatology (1948-2001) and Two Case
Studies
Brandon Smith
Department of Earth and Atmospheric Sciences, University at Albany, State
University of New York, Albany, New York
11:00 am
A Climatology of Warm Season 500 hPa Cutoff Cyclones and Case Study
Matthew J. Novak
Department of Earth and Atmospheric Sciences, University at Albany,
State University Of New York, Albany, New York
11:30 am
Characteristics of Upslope Snowfall Events in Northern New York State and
Northern Vermont: Diagnostics and Model Simulations of Several Northwest-flow
Cases
Daniel P. St. Jean and Paul A. Sisson
NOAA/NWS, Weather Forecast Office, Burlington, Vermont
Noon
A Hail Event Case Study of a Warm Season Closed Low in the Northeast
Thomas A. Wasula
NOAA/NWS, Weather Forecast Office, Albany, New York
12:30 pm
Lunch
Session B. Hydrology and Marine Weather
Session Chair - Alan M. Cope
1:50 pm
Remarks by Session Chair
2:00 pm
A Wind-Wave Climatology for Coastal Buoys Along the United States East Coast
Alan M. Cope
NOAA/NWS Weather Forecast Office, Mt. Holly, New Jersey
2:30 pm
An Early Alert System for Flooding in the Middle Atlantic River Forecast
Domain
Richard H. Grumm
NOAA/NWS, Weather Forecast Office, State College, Pennsylvania
3:00 pm
Challenges Forecasting the Magnitude of Flooding in Southern New England
Associated with the Remnants of Tropical Storm Allison,17 June 2001
Ronald S. W. Horwood
NOAA/NWS, Northeast River Forecast Center, Taunton, Massachusetts
3:30 pm
High Resolution Simulations of Floyd (1999): Structural Evolution and
Responsible Mechanisms for the Heavy Rainfall over the Northeast U.S.
Dr. Brian A. Colle
Institute for Terrestrial and Planetary Atmospheres
State University of New York at Stony Brook, Stony Brook, New York
4:00 pm
A Case Study of Heavy Precipitation Occurring in a Continental Environment
Paul A. Sisson
NOAA/NWS, Weather Forecast Office, Burlington, Vermont
Wednesday, November 6, 2002
Session C. Severe Convection
Session Chair - Josh Korotky
8:15 am
Remarks by Session Chair
8:30 am
A Multi-scale Examination of the 31 May 1998 Mechanicville, New York F3
Tornado
Kenneth D. LaPenta
NOAA/NWS, Weather Forecast Office, Albany, New York
9:00 am
Mesoscale Boundaries, Organized Deep Convection and Forecast
Derailments
Lance F. Bosart
Department of Earth and Atmospheric Sciences, University at Albany, State
University of New York, Albany, New York
9:30 am
Characteristics of Recent Northern New England Tornadoes
John W. Cannon
NOAA/NWS, Weather Forecast Office, Gray, Maine
10:00am
Break
10:30 am
Visually Enhanced Composite Charts for Severe Weather Forecasting and
Real-time Diagnosis
W. Josh Korotky
NOAA/NWS Weather Forecast Office, Pittsburgh, Pennsylvania
Session D. Operations and Instrumentation
Session Chair - Warren R. Snyder
11:20 am
Remarks by Session Chair
11:30 am
A Meteorological Emergency Response Vehicle
William H. Bauman III
Yankee Environmental Systems Inc., Turners Falls, Massachusetts
Noon
National Weather Service Winter Weather Experiment 2001-2002
Michael Bodner
NOAA/NWS, National Centers for Environmental Prediction, Camp Springs,
Maryland
12:30 pm
Lunch
1:30 pm
An Analysis of an Unexpected 12 Inch Snowstorm Across Southern New York State
Michael L. Jurewicz, Sr.
NOAA/NWS, Weather Forecast Office, Johnson City, New York
2:00 pm
Application of Numerical Model Verification and Ensemble Techniques to
Improve Operational Weather Forecasting
Jeffrey S. Tongue
NOAA/NWS, Weather Forecast Office, Upton, New York
2:30 pm
Synoptic and Mesoscale Real Time Forecasting at McGill University
Ronald McTaggart-Cowan
Department of Atmospheric and Oceanic Sciences, McGill University
Montreal, Quebec, Canada
3:00 pm
Break
3:30 pm
Improving Temperature Forecast Verification Scores in the IFPS/GFE Framework
George J. Maglaras
NOAA/NWS Weather Forecast Office, Albany, New York
4:00 pm
GIS Applications in Meteorology, Climatology and Hydrology
John S. Quinlan
NOAA/NWS, Weather Forecast Office, Albany, New York
4:30 pm
An Overview of Key Concepts from the Warning Decision Making Workshop
Richard J. Westergard
NOAA/NWS, Weather Forecast Office, Albany, New York
Acknowledgements
The Fifth Annual Northeast Regional Workshop is planned for
November 4 & 5, 2003
Precipitation Associated with 500 hpa Closed
Cyclones: A Fifty Year Climatology
Anantha R. Aiyyer and Eyad H. Atallah
Department of Earth and Atmospheric Sciences, University at
Albany State University of New York, Albany, New York
In this study, closed cyclones at the 500 hpa level are
identified and their relation to precipitation over the Northeast United States
is examined over a 50 year period form 1950_1999. Data from the NCEP/NCAR
reanalysis and the Unified Precipitation Dataset are used for this purpose. An
objective method is used to identify and classify the closed cyclones into three
categories _ those associated with weak, moderate and heavy precipitation
respectively.
The goals of this study can be summarized as follows:
(1) To contrast the seasonal and interannual frequency of occurrence
of these three classes of closed cyclones.
(2) To examine their tracks and the propagation characteristics.
(3) To examine the spatial distribution of precipitation in
relation to the center as well as tracks of the closed cyclones.
This work is in progress and the results will be reported at the
Workshop.
Anticipating Mesoscale Band Formation in Winter Storms
David R. Novak and Jeff S. Waldstreicher
NOAA/NWS, National Weather Service Eastern Region, Scientific
Services Division, Bohemia, New York
Lance F. Bosart and Daniel Keyser
University at Albany, State University of New York, Albany,
New York
An operational method for anticipating mesoscale band
formation in winter storms is presented. This method draws on results from the
State University of New York at Albany Collaborative Science, Technology, and
Applied Research climatological and composite band study in which 88 cases in
the eastern United States were analyzed during the cold season from November
1996 through April 2001. Composite radar data from these cases were viewed to
develop a band classification scheme. This scheme was then applied to cases from
November 1996 through April 2001. Examination of these 88 cases identified 48
single-banded events, with nearly 80% of these events exhibiting some portion of
their length in the northwest quadrant of the surface cyclone.
Composite results were calculated for cases exhibiting
single-banded events in the northwest quadrant of the surface cyclone and for
nonbanded cases to distinguish synoptic flow regimes associated with banded and
nonbanded cases. The banded composite was marked by cyclogenesis and the
development of a closed midlevel circulation. This flow configuration was
associated with a deformation zone with an identifiable col point northwest of
the surface cyclone. Significant midlevel frontogenesis northwest of the surface
cyclone center coincided with the confluent asymptote of this deformation zone.
The nonbanded composite exhibited a much weaker cyclone located in the confluent
entrance region of an upper-level jet. The absence of a closed midlevel
circulation in the nonbanded composite precluded deformation and subsequent
frontogenesis northwest of the surface cyclone; however, frontogenesis was found
northeast of the surface cyclone associated with midlevel confluence.
Cross-section analysis through respective composite frontogenesis maxima showed
that the nonbanded composite frontal zone exhibited greater conditional
stability than the banded composite frontal zone. The composite results will be
synthesized into conceptual models of banded and nonbanded case evolutions. These results are synthesized into an operational method
which assesses cyclogenesis, deformation, frontogenesis, and conditional
stability in a down-scale approach. This method will be illustrated through
application to the 6–7 January 2002 snowstorm. This storm featured an intense
snowband which was responsible for 30–40 cm of snowfall accumulation in
eastern New York. Illustration of the method will draw on available forecast
guidance and observations from this case from 24 h preceding band formation
through band dissipation.
Snow developed across central and northeastern Pennsylvania
during the late afternoon on January 6th, 2002 as a major storm
developed along the mid-Atlantic coast. Localized, narrow bands of heavy snow
developed within the main snow shield, and produced total snow accumulations of
10 to 20 inches across a region from central Pennsylvania through eastern New
York. The storm developed as an intense, compact mid-tropospheric short-wave
trough lifted northward along the East Coast downstream from a major long-wave
trough located over the Mississippi Valley. This study will compare and contrast
that storm to a second storm that produced a single band of heavy snow across
northern Pennsylvania and southern New York on January 19th. Snow
accumulations within that band reached up to 12 inches across the southern tier
of upstate New York. In contrast to the storm on January 6th, the
storm on the 19th was associated with a relatively weak area of
low-pressure, and a flat, progressive mid-tropospheric flow pattern. The most striking similarity between the storm on January 6th
and the storm on January 19th was that localized bands of heavy snow
developed and played havoc with snowfall forecasts. A comparison of the observed
and model forecast data from both storms indicate that in both cases, the heavy
snow bands developed in areas where the quasi-geostrophic forcing for upward
motion was relatively weak. In the case on the 6th, a pronounced
maximum of quasi-geostrophic forcing for upward motion was forecast, however the
maximum was south of the observed heavy snow area. On the 19th,
strong, organized areas of quasi-geostrophic upward motion forcing were
completely absent. In both cases, the heavy snow developed in association with
frontogenesis associated with frontal boundaries that sloped upward from south
to north across Pennsylvania and southern New York. Cross-sectional analysis of each event indicated that the
snow banding in both cases was likely enhanced by instability located along and
just above the sloping frontal boundary. In the case on January 19th,
a cross-sectional analysis of theta-e indicated that conditional instability was
present above the frontal surface. By contrast, in the case on January 6th
a cross-sectional analysis of theta-e indicated a relatively statically stable
environment above the frontal surface. In that case, evidence is shown that the
environment near the heavy snow bands may have been associated with inertial
instability in the geostrophic wind field. The resulting horizontal
accelerations, as the real wind field attempted to adjust to this unstable
condition, could have resulted in areas of slantwise convection. It is
hypothesized that the small scale of the mid-level short-wave trough with this
event was associated with very sharp downstream ridging, which resulted in the
inertial instability. As was the case with on January 19th, the data
shown for this case indicates the importance of utilizing cross-sections when
diagnosing model data associated with a potential snowstorm. Comparing and
contrasting the data from January 6th and January 19th
also illustrates that a variety of environments can produce banded snowstorms.
A Compare and Contrast Study of Two Banded Heavy Snow Events
Michael S. Evans and Michael L. Jurewicz, Sr.
NOAA/NWS, Weather Forecast Office, Johnson City, New York
Brandon Smith, Lance F. Bosart, and Daniel Keyser
Department of Earth and Atmospheric Sciences, University at
Albany State University of New York, Albany, New York
Daniel P. St. Jean
NOAA/NWS, Weather Forecast Office, Burlington, Vermont
Cutoff cyclones are associated with many significant
forecasting problems in the northeastern United States. Given the complex
terrain in the Northeast, the precipitation distribution associated with
slow-moving cutoff cyclones is often challenging to predict. As an initial step
toward addressing this challenge and as part of our CSTAR research, we present
the results of a 54-year global and regional climatology of 500 hPa cutoff
cyclones in order to map the spatial and temporal distributions of these
features. This task is accomplished by using four-times daily (0000, 0600, 1200
and 1800 UTC) 500 hPa gridded geopotential height analyses from the National
Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR)
reanalysis dataset. Cutoff cyclones are identified objectively. For our purposes,
a cutoff cyclone is defined as a geopotential height minimum surrounded by at
least one closed 30 m interval contour. Cutoffs are identified and catalogued,
and cyclone tracks are constructed, to delineate favored areas for genesis/lysis
and to locate "cutoff freeways." Frequency diagrams showing total
number of cutoff cyclones and number of "cutoff 6 h periods" are
presented for the Northern and Southern Hemispheres and for eastern North
America. Also shown are maps of observed genesis/lysis, the "cutoff grid
point of the year," as well as the "cutoff day of the year."
Histograms of cutoff activity for the Northern and Southern Hemispheres are
presented as well. A case study of two cutoff cyclones that impacted the
northeast US is presented. The two cutoffs shown were both forecast to produce
heavy precipitation in the NWS Burlington CWA, whereas in reality only one of
the systems produced heavy precipitation. Diagnostic analyses are conducted to
identify reasons for the unexpected differences in cutoff behavior and to
illustrate forecast differences.
A Climatology of Warm Season 500 hPa Cutoff Cyclones and Case
Study Cutoff cyclones are associated with many significant
forecasting problems throughout the world, but particularly so in the
northeastern United States. Given the complex terrain found in the Northeast,
the precipitation distribution associated with slow-moving cutoff cyclones is
often a challenge to predict and can wreak havoc among local communities. A climatology of warm season (1 May – 30 September) 500 hPa
cutoff cyclones is derived from four times daily (0000, 0600, 1200, and 1800 UTC)
500 hPa gridded geopotential height fields. The data used are analyses from the
National Centers for Environmental Prediction/National Center for Atmospheric
Research (NCEP/NCAR) reanalysis dataset: 1948–2002. A cutoff cyclone is defined as a geopotential height minimum
surrounded by at least one closed contour based on a 30 m interval. Cutoff
cyclones meeting this objective criterion are identified and catalogued. Cyclone
tracks are determined to delineate favored areas for genesis/lysis and to locate
"cutoff cyclone corridors." Frequency diagrams showing total number of
cutoff cyclones and number of "cutoff 6 h periods" are presented for
the Northern and Southern Hemispheres and for eastern North America. In-progress and future work includes creating objectively
derived tracking products to see if there are favored trends for the orientation
of the "cutoff cyclone corridors" on an annual basis. Our cutoff
climatology will also be used in conjunction with the Unified Precipitation
Dataset (UPD) to map precipitation distributions in cutoff cyclones over the
northeastern United States. A case study will be presented to document the
evolution and environmental impact of a cutoff cyclone.
Over the northeastern United States, northwesterly lower-tropospheric
flow regimes are ocasionally associated with production of heavy precipitation,
especially over the considerable orography of northern New York, Vermont, New
Hampshire and western Maine. Two cutoff 500 hPa cyclone events in the autumn of
1999 produced heavy snowfall over the mountains of northern New York State and
northern Vermont. These two cases provided an operational impetus for studying
the characteristics of upslope snowfall events. The goal of this research is to
produce ingredients-based conceptual models and operational methodologies for
the purpose of improved prediction of the precipitation patterns produced by
these flow regimes in the complex terrain of the northeastern United States. Cases selected for this study were limited to events
occurring with prevailing deep-tropospheric northwesterly flow, which excluded
any cases involving rapid-genesis coastal cyclones (i.e., Nor’easters).
Northwest-flow scenarios generally produce a significant low-level flow
component orthogonal to the Green Mountains and Adirondack Range, which is
favorable for the generation or enhancement of heavy precipitation by orographic
lift. To date, six scenarios have been examined in this study: three events
which produced heavy snowfall northern Vermont and northern New York State; two
events which had been forecast to produce heavy snowfall, yet significant
precipitation failed to occur; and one very weak northwest-flow event. NCEP/NCAR Reanalysis data were used in determining the
synoptic-scale characteristics of each of the cases, supplemented with ETA model
BUFR sounding analysis data in order to interrogate the mesoscale structure of
each event. Additionally, 5-km grid spacing mesoscale ETA model simulations have
been performed both to isolate mesoscale signatures, and for comparison with
their coarser-resolution operational ETA model (40-km) counterparts. Diagnostic
findings from this study suggest several meteorological factors significant to
the development of heavy precipitation from this type of flow regime: (a) the
low-level moisture profile; (b) the strength and orientation of the low-level
wind with respect to the orography; (c) the low-level static stability profile.
Low- and high-resolution model comparisons have yielded some measure of forecast
success by the 5-km ETA. Operational forecast procedures and techniques
currently in development will be presented, as will direction for future
investigation.
Warm season closed lows provide a variety of severe weather
across the Northeast ranging from large hail events to significant flash
flooding. On 28 May 2001, Memorial Day, a closed low moving equatorward from
Hudson Bay into the Great Lakes Region initiated numerous large hail producing
thunderstorms. The severe weather event consisted primarily of hail from penny
(1.9 cm) to golf ball size (4.4 cm). The National Weather Service at Albany’s
County Warning Area had over a half dozen of its counties impacted. Some
counties were hit by large hail multiple times. Late spring crop and orchard
damage occurred in portions of Eastern New York. Current CSTAR warm season
closed low climatology research has shown that there are several categories or
tracks of closed lows. A subjective analysis was performed to create a warm season
(May 1st to September 30th) climatology of closed lows
from 1980-2000 based on daily 500 hPa and surface analyses across the
latitude-longitude domain of 36 A strong "closed" upper low and its occluded front
triggered the severe weather on Memorial Day. The thunderstorms began to develop
around noontime with the maximum diurnal heating. The instability generated
between the cold pool aloft and the surface heating helped initiate the
thunderstorms. Over the next several hours many pulse thunderstorms developed
over the Greater Capital Region, the upper Hudson River Valley, and Western New
England. A multi-scale analysis will be shown for the 28 May 2001
event to address what caused the hail episode in the Northeast. Various ETA and
AVN model grids, surface observations, upper-air data including soundings,
cross-sections and Doppler radar data including Vertically Integrated Liquid (VIL)
values will be examined. The importance of the cold pool aloft, lapse rates,
vorticity advection, and upper-level jet streaks will be stressed in the
generation of the hail producing pulse thunderstorms.
Approximately fifteen years of hourly meteorological data
from several moored buoys along the northeast U.S. coast have been examined,
with the goal of developing an operationally useful climatology of winds and
waves. The buoys examined were 44009 (Delaware Bay), 44025 (south of Long
Island), 44013 (near Boston) and 44007 (near Portland Me). The data were
obtained from the National Data Buoy Center’s Internet Web site as text files,
which were imported into a spread sheet program for sorting, analysis, and
creation of chart displays. Each hourly report contains the wind direction, wind
speed, significant wave height, dominant wave period, and various other
meteorological information. The primary goal was to determine average wave height as a
function of wind speed and direction. Theoretically, the height of wind-driven
waves depends mainly on wind speed, fetch length, and time. For near-shore
locations, the fetch length varies greatly with wind direction. Thus wind speed
and direction account for two of the three factors (excluding wind duration).
Besides duration, this analysis does not account for waves generated by distant
storms. Therefore, the presentation of results will include primarily
wave height means and standard deviations as a function of wind direction (eight
compass points) and wind speed (five knot bins) for the four coastal buoys along
the mid-Atlantic and northeast U.S. coast. At the Delaware Bay buoy (44009), for
example, the highest waves for a given wind speed tend to occur with a northeast
wind, and the lowest with a southwest or west wind (see attached chart). Similar
results can be shown for the other buoys. This likely results from the greater
frequency of sustained northeast winds with coastal storms. However, each buoy
has a unique wind-wave profile depending on the nearby coastline. In addition to
wave heights, wind frequency as a function of speed and direction will also be
shown. It is hoped that the results of this study will be useful as
guidance for marine forecasters at offices along the northeast U.S. coast, and
perhaps could be incorporated into "Smart Tools" for the marine
portion of the Interactive Forecast Preparation System.
The challenge of flash flood forecasts continues to perplex
forecasters. This system offers a paradigm shift in our thinking about flash
flood predictions. To date, the main focus of advances in assessing the
possibility of flash floods has been on operational mesoscale models and
improved quantitative precipitation forecasts, despite the fact that some
studies indicate the serious shortcomings of convective parameterization schemes
(Gallus, 1999). Even with rapid advances in processing speeds, the forecast
community has reached a plateau in flash flood prediction which will likely not
be changed until cumulus scale models are quasi_operational, perhaps within five
years. While cumulus scale models may hold high hopes, many areas will still be
at risk of flash flooding during the next half decade of development. This
system offers a bold initiative to increase advance watches and warnings of
flash flooding, specifically for the Middle Atlantic River region, but with
applications elsewhere in the nation. The foundation of this system is the research by Grumm and
Hart (1999) establishing a real_time operational assessment of climatological
anomalies of various model forecast fields based on derived monthly means from
the NCEP reanalysis work (1948_2000). Since October 1999, the National Weather
Service Office in State College has been producing graphical displays of model
forecast anomaly fields for the Eta, Aviation, and the locally run MM5 computer
models. Anomaly fields consist of the vertical mass_weighted mean anomaly for
height, temperature, wind and moisture. These parameters are compared to the
climatological mean to determine the anomaly. This anomaly system, developed by
Grumm and Hart, is being used to create anomaly fields for historically
significant rainfall events over the MARFC domain dating back to 1948. These
significant rainfall events will be chosen based on the observed/estimated
rainfall values. Once anomaly fields have been created, a pattern recognition
exercise will be conducted to classify these events by time of year and
significant types (ie. narrow cold frontal rain bands, mesoscale convective
systems, etc.) This project will determine the atmospheric anomalies
associated with flash flooding in each month over the MARFC domain. The premise
of this project is that there are characteristic signatures of flash flooding in
the departure from mean fields of a variety of NCEP reanalysis data variables.
That is, by month and season, flooding and flash flooding in the Middle Atlantic
region has a fingerprint, so to speak, of anomalies that when predicted by
current operational models and assessed by the Grumm_Hart model comparison
fields will yield an early alert to flooding. On 17 June 2001, Father’s Day, the remnants of once
Tropical Storm Allison tracked across southern New England, dumping as much as
six inches of rain in a three to nine hour period. Widespread flash flooding
affected portions of southeastern New York, Connecticut, Rhode Island and
eastern Massachusetts. Mainstem rivers also sharply rose. Many mainstem rivers
approached bankfull and some exceeded flood stage, most notably the Yantic River
at Yantic, Connecticut and Neponset River at Norwood, Massachusetts. The extreme
intensity of the rainfall over such a short period of time, coupled with
difficulties in obtaining real-time measurements of river stage and
precipitation resulted in significant challenges forecasting the magnitude of
the flooding along mainstem rivers in Southern New England. Through use of sound hydrometeorological practices,
forecasters at the Northeast River Forecast Center (NERFC) utilized modified
unit hydrographs in order to issue operational forecasts that were significantly
better than model forecasts using the default unit hydrographs contained in the
river model. This presentation will provide an overview of the
hydrometerological conditions leading to the storm, as well as a review of the
forecast procedures used at the NERFC to provide forecast services at several
locations impacted by the storm. It will also address several of the challenges
that faced the forecasters during this event and how these can be addressed in
the future.
Matthew J. Novak, Lance F. Bosart, and Daniel Keyser
Department of Earth and Atmospheric Sciences, University at
Albany
State University of New York, Albany, New York
Thomas A. Wasula and Kenneth D. LaPenta
NOAA/NWS Weather Forecast Office, Albany, New York
Daniel P. St. Jean and Paul A. Sisson
NOAA/NWS, Weather Forecast Office, Burlington, Vermont
Thomas A. Wasula and Kenneth D. LaPenta
NOAA/NWS, Weather Forecast Office, Albany, New York
Matthew J. Novak
Department of Earth and Atmospheric Sciences, University at
Albany
State University of New York, Albany, New York
Alan M. Cope
NOAA/NWS Weather Forecast Office, Mt. Holly, New Jersey
Richard H. Grumm and David J. Ondrejik
NOAA/NWS, Weather Forecast Office, State College, Pennsylvania
Paul G. Knight and Justin M. Brolley
Pennsylvania State Climate Office
Penn State University, University Park, Pennsylvania
Ronald S. W. Horwood
NOAA/NWS, Northeast River Forecast Center, Taunton,
Massachusetts
Early on the morning of September 16th 1999
hurricane Floyd made landfall on the North Carolina coast and moved rapidly
northeastward. The winds associated with Floyd weakened rapidly after landfall,
but a swath of heavy precipitation developed ahead of the storm from North
Carolina to New England. Over the Northeast, the heaviest precipitation (20-40
cm) fell in 12-18 h across northern New Jersey, southeastern New York, and
central Connecticut, resulting in over one billion dollars in flood damage and
16 fatalities over the Northeast. Even 24 hours leading up to the event, the
operational NCEP models failed to properly forecast the magnitude and location
of heavy precipitation. The purpose of this study is to use the Penn State-NCAR
Mesoscale Model (MM5) down to 1.3 km grid spacing to objectively evaluate how
well this modeling system can simulate the evolution of Floyd and the heavy
precipitation over the Northeast. The MM5 was also used to diagnose the physical
mechanisms for the heavy rainfall by conducting simulations to separate the
effects of latent heating, surface heat fluxes, and local topography on the
circulations and strengthening baroclinic zone near the coast. The MM5 was initialized at 0000 UTC 16 September 1999 using
the NCEP Eta model interpolated on a 40-km grid. The MM5 was nested using a
one-way interface over the Eastern U.S. at 36,12, 4, and 1.3 km grid spacing,
with the highest resolution over southern New England. The control run of the
MM5 used the Grell convective scheme (at 36- and 12-km grid spacing), MRF PBL
scheme, Reisner2 microphysics (which includes graupel and super-cooled water),
and the Dudhia radiation scheme. The MM5 precipitation was verified against all
available Cooperative observer and NWS rain gauges by interpolating the MM5
precipitation to the observation points. Even though the MM5 was initialized using the NCEP Eta, the
36-km MM5 produced a much better quantitative precipitation forecast than the
32-km Eta over the Northeast U.S. By trying several different convective and PBL
parameterizations in the MM5, it was determined that the BMJ convective scheme
in the Eta may have contributed to a much weaker storm and under-predicted
precipitation amounts. The precipitation distribution was also sensitive to the
Eta sea surface temperatures (SSTs), since using the higher resolution Navy OTIS
SSTs in the MM5 resulted in a better forecast of the maximum precipitation
location. The MM5 at 4- and 1.3 km grid spacing realistically simulated the
20-40 cm of precipitation over the flooded areas, but over-predicted the amounts
at many locations. A MM5 simulation without topography still resulted in 20-40
cm of precipitation at high resolution and very little difference in storm
track; therefore, the inland terrain played a secondary role in enhancing the
heavy precipitation when compared to the deep frontogenetical circulation. A
simulation without surface heat fluxes resulted in a 5-10 mb weaker storm
shifted 100-200 km farther east, with 30-50% less precipitation. Another
simulation without diabatic precipitation effects resulted in a 20-30 mb weaker
storm that did not propagate up the coast. Therefore, diabatic effects from
precipitation and surface fluxes were critical in maintaining the storm motion
and frontogenetical circulations, even as Floyd transitioned to extra-tropical
along the coast. This research focuses on the physical processes relating to a
recent event of precipitation in which at least 25 mm of liquid equivalent
precipitation occurred within a 12h period. The event of 7 January 2002 was that
of heavy snow in southern Vermont and the Albany, New York regions that was
evidently unrelated to topographic forcing. In the Burlington County Warning
Area, the intensity of the precipitation was not forecasted by the operational
models 24 hours before the event. Although the case occurred in a large_scale
flow that was favorable for cyclogenesis, several crucial details relating to
the extreme mesoscale development are identified and studied. Additionally,
cyclogenetic mechanisms are studied. The mesoscale environment is studied in the context of both
upright and slantwise convection. The processes that were responsible for this
destabilization include upper_level cooling associated with the advance of an
upper_level short_wave trough, and the development of conditional symmetric
instability and coupling with the dynamic tropopause. Frontogenetic forcing was especially large in the middle
troposphere in each case. The fact that ascent maxima of _20 to _50 microbars
per second occurred in the vicinity of these zones of frontogenesis suggest the
importance of this forcing contributing to the event's strength. A synoptic overview of the 7 January 2002 heavy snow event
will be presented showing the distribution of the heavy snow, radar
reflectivity, and upper air signatures. Mesoscale model output from the NCEP ETA
and the McGill MC2 depicting the utility of dynamic tropopause for tracking the
intensity of the upper level short_wave trough and the coupling to the lower
troposphere will be shown. Finally, suggestions for use by the operational
forecaster will be presented.
High Resolution Simulations of Floyd (1999): Structural
Evolution and Responsible Mechanisms for the Heavy Rainfall over the Northeast
U.S.
Dr. Brian A. Colle
Institute for Terrestrial and Planetary Atmospheres
State University of New York at Stony Brook
Stony Brook, New York
John R. Gyakum and Ronald McTaggart_Cowan
Department of Atmospheric and Oceanic Sciences, McGill
University
Montreal, Quebec, Canada
Paul A. Sisson
NOAA/NWS, Weather Forecast Office, Burlington, Vermont
Garry Toth, Peter Lewis and John K. Parker
Meteorological Service of Canada
A Multi-scale Examination of the 31 May 1998 Mechanicville,
New York, F3 Tornado
Category F3 or greater intensity tornadoes are rare in
eastern New York and western New England with only six since 1950. On 31 May
1998, an F3 tornado struck Mechanicville, New York, injuring 66 people and
causing 71 million dollars in damage. The tornado was part of a widespread,
severe weather outbreak across the Northeast that killed five, produced 30
tornadoes, 369 reports of wind damage and 151 reports of large hail. This paper
will review the synoptic conditions that spawned the severe weather, as well as
examine the mesoscale and storm scale environments that produced the
Mechanicville tornado. The upper level pattern that produced the 31 May 1998 tornado
outbreak began to evolve during the week prior to the event. An upper level
closed low moved south into Hudson’s Bay on 26 May and remained there for much
of the next week, finally moving through the Canadian Maritimes on 4-5 June.
Short waves rotating around it spawned three major northeastern United States
severe weather outbreaks (29 May, 31 May and 02 June). The 31 May outbreak was
enhanced by a second short wave that ejected out of another closed upper level
low that moved south from the Gulf of Alaska (20-24 May) to the coast of
California (30 May). At 250 hPa, the coupling of two strong (130 kt) jets helped
generate a large area of enhanced upward vertical motion. In response to the
strong upper-level dynamics, unseasonably strong surface low pressure (986 hPa)
strengthened as it moved from the northern Plains States through the Great Lakes
into eastern Canada. A very strong low-level jet (55 kt) provided the mechanism
to rapidly transport a very warm, moist airmass over the Ohio Valley into the
Northeast and contributed to high shear and helicity in the lower troposphere. During the afternoon of 31 May, the warm front associated
with the surface low moved through eastern New York. In the warm sector, CAPE of
around 2000 J kg-1, storm-relative helicity of greater than 450 m2
s-2 and 0-6 km shear greater than 25 m s-1 indicated
the potential for supercells and tornadoes. Terrain may have played a role in
further enhancing the tornadic potential of the Mechanicville storm as it moved
into the immediate Hudson Valley. The southwest low-level flow over the high
terrain to the west was channeled to a more southerly direction in the valley,
increasing low-level shear and helicity. The southerly flow also advected warm,
moist air poleward more rapidly than in surrounding high terrain areas
increasing instability. A line of thunderstorms in western New York at 1600 UTC
intensified and moved east producing locally severe weather as it reached
central New York at 1824 UTC, about two hours prior to the Mechanicville tornado
touchdown. At that time, a small cluster of isolated storms developed about 55
km to the east of the line. One of these storms intensified as it moved
east-northeast. By 1942 UTC it had turned severe and was about 30 km ahead of
the line. The lead cell moved into the somewhat more unstable and more highly
sheared environment of the Hudson Valley about 2000 UTC. Tornado touchdown
occurred at 2022 UTC, about the time the outflow from the line of storms to the
west caught up with the lead cell.
In recent years forecast train wrecks have often been
associated with errors involving the representation of mesoscale boundaries and
organized deep convection in numerical models as much as synoptic_scale forecast
errors. Mesoscale boundaries serve as loci for concentrated thermal, moisture
and vorticity gradients. Failure to resolve these boundaries properly in
numerical models can adversely affect the timing, location, intensity and
duration of forecast precipitation. Organized deep convection is important in
enhancing downstream ridge/jet development. Failure to properly resolve the bulk
upscale effects of organized deep convection in numerical models can hinder the
self development process during cyclogenesis. A significant additional problem is that critical mesoscale
boundaries often hide in plain sight, often making themselves known as the
forecast is going down in flames. This state of affairs can arise because our
enormous database of surface observations is vastly underutilized by models and
forecasters alike. Reasons for this problem will be discussed and illustrative
examples will be shown. Our understanding of northern New England tornadogenesis is
limited. They tend to be short lived, ill-defined and often do not exhibit radar
and environmental characteristics of their Midwest tornado counterparts. They
are elusive and accompanied by little or no warning lead time. Storms that
produce tornadoes in northern New England sometimes do not even exhibit radar
characteristics that typically result in the issuance of severe thunderstorm
warnings. Automated detection schemes have not faired well either. Other
complications, such as visibility restrictions due to rugged terrain and the
deeply forested and rural nature of the region, degrade the ability for visual
detection. To help mitigate the impact of detection limitations and
improve preparedness in the warning process, this study was conducted to produce
a composite tornado day in northern New England. Environmental conditions will
be discussed and compared to the Johns and Dorr (1996) study of strong and
violent tornado episodes across an expanded New England-wide domain. A frequency
distribution created from the Storm Prediction Center tornado data set will be
presented. Mesoscale and synoptic features will be combined with radar
information to derive a composite tornado environment. Topographical maps will
be superimposed with tornado touchdowns to identify correlations of varied
terrain with tornadogenesis. Finally, commonly used convective parameters
derived from modeled soundings will be examined to demonstrate a tornado case in
a high shear, low instability regime. Given the growing volume of forecast and observational data,
it is becoming increasingly important for forecasters to extract scientifically
relevant information quickly before and during severe weather forecast and
warning operations. During this presentation, composite charts of model forecast
fields will be supplemented with composite charts of hourly surface analysis to
highlight the physical processes supporting severe storm development, convective
organization, and storm mode. To capture this information, composite charts are
designed to illustrate 1) measures of instability and vertical wind shear, 2)
three dimensional moisture availability, content, and distribution and, 3)
synoptic and mesoscale forcing mechanisms. Composite charts are effective
because they highlight important information, rather than exposing all possible
information. By using color, images, and contours effectively, the presented
charts allow forecasters to quickly focus on the most important information,
resulting in quick recognition of the convective potential. This presentation highlights a severe convective wind event
that effected parts of Ohio, Pennsylvania, West Virginia, New York, and Maryland
on 9 March 2002. It will be shown that visually enhanced composite charts
promote quick recognition of the contributing forecast and real-time severe
weather processes. Composite charts presented here focus on evaluating the large
scale potential for severe weather with the Eta, and monitoring the evolution of
the convective environment with the hourly Rapid Update Cycle (RUC). In this
context, information from the hourly RUC provides a critical link to the model
forecasts. Successive runs of the Eta indicated 1) significant vertical
wind shear associated with an anomalously strong low-level jet, 2) moderate
moisture and, 3) considerable low-level forcing from a combination of strong
moisture flux convergence and frontogenesis along a vigorous frontal system.
Instability was forecast to be the primary limiting factor; the warm sector
environment was expected to become only weakly unstable, with CAPE forecast to
remain less than 500 jkg-1, and the Best Lifted Index (BLI) expected
to reduce no further than -2. The large scale potential thus suggested the
possibility of a narrow frontal squall line with strong convective wind gusts,
but weak instability would probably limit the areal extent of severe weather. Hourly RUC composite charts substantiate the convective
potential noted in the Eta forecasts, but also show that the real-time
environment was becoming significantly more unstable than the model forecasts;
actual CAPEs were greater than 1300 jkg-1, and BLIs were -3 to -6
during the early evolution of the squall line. Greater instability increased the
expectation for severe weather, and indicated a growing potential for widespread
wind damage. This information was critical to understanding the evolving
convective potential, and contributed to effective warning decisions. A self-contained meteorological emergency response vehicle (MERV)
is described that provides emergency management weather support during natural
disasters and/or homeland defense incidents by integrating this new technology
into operational weather support. Fully automated on-site surface and upper air
meteorological data is required to feed dispersion models during nuclear,
chemical, or biological weapon attacks, as well as during natural disasters
where conventional weather observations are unavailable (forest fires,
earthquake aftermath, etc.). The system provides continuous automated in-situ
measurements of surface pressure, temperature, humidity (PTU), and winds, as
well as full upper air profiles from radiosondes and low level PTU and winds
from a tethersonde. In addition, it provides remote sensing of boundary layer
winds from Doppler lidar and present weather images from a color total sky
imager. The sky imager with its horizon-to-horizon view is used to provide users
with near real-time images of sky cover and visibility. The system is envisioned to be deployed by unskilled
personnel and can be operated with minimal user training, avoiding the need for
a trained meteorologist. Internet connectivity provides remote monitoring,
control and diagnostics, and real time data is output in standard meteorological
formats. The core of the system is an automated radiosonde launcher mounted on a
trailer or pickup truck, which supports the other met sensors. The launcher is
capable of automatically inflating and releasing sequences of multiple
radiosondes at predetermined times or remotely on demand. The launcher uses
standard radiosondes from most manufacturers. Alternately, a tethersonde can be
deployed providing PTU and winds about every 250 m up to 1.5 km altitude. An
eye-safe Doppler lidar is used to obtain high-resolution boundary layer winds,
providing u, v, and w wind components in the boundary layer. Measuring the
vertical moment of the wind will provide a valuable input to transport models to
determine the three dimensional dispersion of a substance such as radioactive
fallout.
Kenneth D. LaPenta NOAA/NWS, Weather Forecast Office, Albany,
New York
Lance F. Bosart
Department of Earth and Atmospheric Sciences, University at
Albany, State University of New York, Albany, New York
John W. Cannon
NOAA/NWS, Weather Forecast Office, Gray, Maine
Historically, an average of four tornadoes occur each year
across the northern New England states of Maine, New Hampshire and Vermont. In
recent years, tornado frequency has diminished. It contradicts the expectation
of increased tornado detection commonly associated with the deployment of highly
sensitive Doppler radars and population increases. Most are classified as
"weak" (F0-F1) on the Fujita scale, but "strong" tornadoes
(F2-F3) do occur.
for Severe Weather Forecasting and Real-time Diagnosis
W. Josh Korotky
NOAA/NWS, Weather Forecast Office, Pittsburgh, Pennsylvania
William H. Bauman III and Mark C. BeaubienYankee Environmental
Systems Inc.
Turners Falls, Massachusetts
During the period November 1, 2001 through May 1, 2002 the
National Weather Service (NWS) conducted a Winter Weather Experiment (WWE).
Participants included eight Eastern Region Weather Forecast Offices (WFOs),
three components of the National Centers for Environmental Prediction (NCEP) -
the Hydrometeorological Prediction Center (HPC), Environmental Modeling Center
(EMC), and NCEP Central Operations (NCO), with project oversight from the NWS
Office of Climate Weather and Water Services (OCWWS). The goal of the experiment
was to enhance winter weather services to the public via a suite of enhanced
products from HPC for use by the WFOs in support of the their winter weather
watch and warning program. Two secondary objectives were also addressed during the
experiment. The first was to test NCEP’s newly implemented experimental Short
Range Ensemble Forecast (SREF) system and its application to winter weather
forecasting. The second was to test HPC’s anticipated role of collaboration
with the WFOs as a prototype to the paradigm envisioned to be utilized during
the upcoming National Forecast database (NDFD) era. The suite of enhanced products produced by HPC incorporated
output from the 10 member 48km SREF system in addition to model output routinely
available to HPC. The combination of SREF and operational model output allowed
HPC to produce ensemble based winter storm watch/warning graphics for snow and
ice accumulations. These graphics depicted the percent the ensemble based
prediction of snow and ice accumulation would exceed 24 hour winter storm watch
criteria for each county within the WWE area. In addition, an ensemble based low
tracks graphic was produced and depicted the expected paths of major surface
lows through 72 hours at 12 hour intervals. This graphic also depicted the
spatial uncertainty of the location of the surface low. In addition, a text
discussion conveying meteorological reasoning for the graphics, the storm
potential and uncertainty for forecast day 4 through 7 was also provided.
Results from the experiment will be presented and will include subjective
feedback from WWE participants (WFO and NCEP HPC) on the utility of the WWE and
the performance of the SREF during the WWE. Further, an introduction to this
year’s WWE (2002-2003) will be provided as well.
During the afternoon and early evening hours of 19 January
2002, a narrow band of heavy snowfall affected portions of northern Pennsylvania
and southern New York. This band was roughly 30 kilometers wide, with the most
intense and persistent snowfall rates oriented west to east from near Elmira,
New York across the Binghamton, New York area, then further eastward into the
Catskill mountain region. Storm totals of eight to 12 inches in about a six hour
period were common within this small corridor. This event had some unique characteristics that likely
contributed to its "surprise" nature. First, the prevailing flow
pattern was flat and progressive as indicated by observed upper air and well
initialized model data. This led to weak patterns of vorticity and thermal
advection at levels where standard meteorological analysis are typically
performed. Second, a strong upper level speed maximum was located from New York
state into southern New England, with the more favorable entrance region of this
upper level jet core across the Mid-Atlantic region, well south of the heavy
snow band. Third, despite uniform liquid equivalent precipitation totals
(generally 0.20" to 0.30") observed across New York and Pennsylvania
for this event, actual snow accumulations varied widely across the region.
Interestingly, the models’ quantitative precipitation forecasts (QPF) were
consistent and fairly accurate. So why did heavy snow develop? A cross-sectional inspection
of observed and model data during the time of heavy snowfall revealed a frontal
boundary that sloped upward from south to north, with the northern extent of the
front located across New York and Pennsylvania. Strong frontogenetical forcing
in mid-levels of the atmosphere was associated with the frontal zone over
southern New York. Additionally, pronounced diffluence developed just above the
zone of frontogenesis as the area came under the exit region of a 500 mb jet
streak moving through the central Appalachians. This juxtaposition created a
shallow, but vigorous circulation promoting strong lift between 600 and 500 mb.
Cross-sectional analysis also revealed an area of weak conditional instability
in a shallow layer just above the frontal zone, near 500 mb. This instability
would have acted to enhance and localize the circulation associated with the
frontogenesis, and could have resulted in localized areas of convection,
reinforcing the intensity of the banded feature associated with frontogenesis.
Finally, another key contributor to the heavy snow appeared to have been a
thermal structure supportive of favorable snow growth mechanisms within a deep
and saturated layer. This aspect was well portrayed by hourly sounding profiles.
It is theorized that each of the above factors played a significant role, with
the absence of any one of them possibly resulting in far less snowfall. This case study showed the potential value of viewing model
fields using cross-sections. Particularly when mechanisms of interest are
shallow in nature, they could fall between mandatory or significant levels or be
"smoothed out" if looking at a mean layer in plan view.
During the past several years, real-time numerical weather
prediction has spread rapidly from operational centers such as the National
Centers for Environmental Prediction (NCEP) to universities, government
agencies, and private industry. For example, the Stony Brook University (SBU)
has been running the Penn State-National Center for Atmospheric Research
mesoscale model (MM5) in real-time since the fall of 1999. The SBU MM5 is run
for both the 0000 and 1200 UTC cycles at 36-,12-, and 4-km horizontal grid
spacing. Data are available in NetCDF format for ingestion and integration with
other data sets in meteorological workstations, such as the National Weather
Service’s (NWS) Advanced Weather Interactive Processing System (AWIPS). The
data can also be visualized via the Internet. In order for these regional modeling efforts to help
operational forecasters and model development, it is imperative that objective
verification of the model forecasts be completed, with the results effectively
passed to the forecaster. SBU has been verifying the MM5 against all available
observations over the Eastern U.S. The results have also been compared with the
NCEP eta model. SBU has also teamed with the NWS Upton, NY to learn how to use
mesoscale model output in an operational mode and to learn the strengths and
weaknesses of the MM5 modeling system. A Cooperative Program for Operational
Meteorological Education and Training (COMET) Partners Project was completed and
some of the results will be presented at the workshop. Recently, SBU, the NWS Forecast Offices at Upton, New York,
Taunton, Massachusetts, and Mt. Holly, New Jersey, as well as, the Northeast
River Forecast Center and the Eastern Region Headquarters were awarded a new,
three-year contract from COMET to examine this problem in more detail. In
addition to scientific aspects, the goals of this ongoing effort are both
operational forecasting and educationally oriented. Scientific goals include
evaluation of model sensitivity to initial conditions, parameterized physics, as
well as, quantifying the benefits of event-based verification versus
conventional seasonal average verification. Operational forecasting goals
include developing operationally oriented visualization tools for mesoscale
models, ensembles and verification data sets. Lastly, educational goals include
training forecasters to understand and utilize mesoscale models, ensembles and
real-time verification more effectively in the forecast process. This presentation will discuss the results from previous work
and plans for the three-year COMET collaborative effort that has recently
started.
Full implementation of a real-time forecasting system at
McGill University was completed on 30 May 2002. The forecast office of
Environment Canada in St. Laurent, Quebec, and the National Weather Service
Forecast Office in Burlington, Vermont, have been providing feedback on this
forecast effort. The system includes a once-daily (0000 UTC) 48-h run of the
Mesoscale Compressible Community (MC2) model employing a triple-nesting strategy
with grid spacings of 36, 12, and 3km. An accounting of the system’s
performance timings and statistics will be presented. The 36-km domain extends
from the central plains to beyond the Atlantic continental shelf. The 12-km
domain encompasses a region bounded by Lake Michigan to the west, and the
eastern seaboard. The high-resolution 3-km domain focuses on the Champlain and
St. Lawrence Valleys. Data for initial and boundary conditions are supplied by
the 0000 UTC forecast run of the operational Canadian Global Environmental
Multiscale Model. The system’s domains focus in on the southwestern Quebec and
Champlain Valley region with the goal of evaluating high-resolution
deterministic forecasts of precipitation amounts for southern Quebec and the
northeastern states. Specifically, we wish to examine the influence of channeled
flows on precipitation patterns and mesoscale frontogenesis in the St. Lawrence
and Champlain Valleys. We present a diagnosis of the output from the real-time
forecasting system in the form of a case study validation for the 0000 UTC run
of 27 September 2002. A heavy cloud shield and rainband on the northern leading
edge of the transitioned ex-hurricane Isidore transited the forecast region from
1200 UTC 27 to 1200 UTC 28 September, and resulted in 24-hour precipitation
accumulations of greater than 50 mm at numerous upstate New York and New England
stations. We present validation of the three forecast domains, and compare
dynamic tropopause analyses from the forecast cycle with those produced by the
Rapid Update Cycle (RUC). The later verification will ensure that the
large-scale model dynamics resemble the observed evolution of the case study,
while the former deals with the interaction of synoptic to mesoscale dynamics
and thermodynamics. Additionally, a case of severe squall-line convection
occurring at 0000 UTC 18 July 2002 is investigated and verified against enhanced
satellite imagery and two special radiosonde launches from the McGill-operated
St. Hilaire Research Station. One of the ascents took place in the pre-storm
environment, and the other during the convective burst. The latter balloon
penetrated the updraft core (vertical velocities in excess of 15 m/s were
observed), providing a unique opportunity for us to verify the storm’s
intensity on the high-resolution sub-domain with observational data. The MC2
real-time forecasting system is shown to have predicted the storm remarkably
well for a 24-h lead time. Despite having the superior MAV guidance available, improving
model forecasts, and two years to become familiar with verifying MAX/MIN
temperatures at GFL and POU, and for the fifth period, Albany forecasters have
made little progress in improving their scores during the ICWF/IFPS/GFE
transition period. Now that Albany forecasters have become familiar with how to
prepare the grid field forecasts, a plan was recently implemented in order to
help Albany forecasters increase their focus on verification of their
temperature forecasts. This plan will involve a multi-step approach, and will
include the creation of locally derived smart tools to create better temperature
grid field forecasts. The plan will also involve raising forecaster awareness as to
which temperature forecast guidance is best, and how to incorporate it into
their grid field forecasts. For example, MAV MOS guidance has routinely done
better than the FWC guidance since its inception. However, verification scores
show that on a routine basis, the average of the MAV and FWC temperature
forecasts provides the best forecast overall. Finally, individual one on one training will be provided to
each forecaster in order to insure that they understand how the current
verification system works within the IFPS/GFE framework. Key components of this
training will be discussed.
Geographic Information Systems (GIS) lets users link
relational databases to spatial analysis. It is this link which has great
applications when it comes to dealing with large quantities of meteorological,
climatological and hydrologic data. The primary purpose of this presentation
will be to introduce the audience to GIS through a spatial analysis of data sets
commonly used in the NWS ranging from verification data to forecast analysis and
procedural practices. Detailed spatial analysis will be presented which focuses
on the Cooperative Observer Program, Forecast Grid Fields across Eastern Region,
as well as Procedural Issues including Winter Weather Thresholds and the
Determination of the Growing Season. Applications of GIS in Hydrology will also
be examined from looking at basinwide average precipitation fields to
highlighting individual creeks which may be susceptible to flooding. Two concepts gleaned from the Summer 2002 Warning Decision
Making Workshop will be presented. The presentation will emphasize the need, and
techniques for conducting post mortems of severe weather events. The
presentation will show lead forecasters or other supervisors how to recognize
fatigue symptoms of front line staff during a severe weather event, and how to
best utilize the available staff. Various techniques such as rotating duties
among available employees and others will be discussed.
Michael Bodner
NOAA/NWS, National Centers for Environmental Prediction
Camp Springs, Maryland
Across Southern New York State
Michael L. Jurewicz, Sr. and Michael S. Evans
NOAA/NWS, Weather Forecast Office, Johnson City, New York
Jeffrey S. Tongue
NOAA/NWS, Weather Forecast Office, Upton, New York
Dr. Brian A. Colle
Marine Science Research Center
State University of New York at Stony Brook
Stony Brook, New York
Alan M. Cope
NOAA/NWS, Weather Forecast Office, Mount Holly, New Jersey
Robert C. Shedd
NOAA/NWS, Northeast River Forecast Center, Taunton,
Massachusetts
David R. Vallee
NOAA/NWS, Weather Forecast Office, Taunton, Massachusetts
Joshua Watson
NOAA/NWS, National Weather Service Eastern Region, Scientific
Services Division, Bohemia, New York
Ronald McTaggart-Cowan and John R. Gyakum
Department of Atmospheric and Oceanic Sciences, McGill
University
Montreal, Quebec, Canada
Paul A. Sisson
NOAA/NWS, Weather Forecast Office, Burlington, Vermont
George J. Maglaras
NOAA/NWS Weather Forecast Office, Albany, New York
Since the introduction of the Interactive Computer Worded
Forecast system (ICWF), and later the Interactive Forecast Processing
System/Graphical Forecast Editor (IFPS/GFE) system, for public forecast
preparation, forecast verification has become a secondary concern to most
forecasters at WFO Albany, and probably most other offices. For the past two
years, the focus of most forecasters has been on learning how to use these
systems to prepare their forecasts, and on getting through the labor intensive
day-to-day task of preparing grid field forecasts for the public forecast
elements, without much attention being paid to the accuracy of their forecasts.
Compared to long-term trends, MAX/MIN verification scores for Albany (ALB) have
remained relatively stable in terms of their percent improvement over FWC (NGM
MOS) forecasts for the first four periods. However, for the past two years, the
percent improvement over the MAV (AVN MOS) forecasts has remained substantially
negative. In addition, during the past two years, MAX/MIN forecasts for Glens
Falls (GFL) and Poughkeepsie (POU) have also been verified, as well as fifth
period forecasts for all three stations. These scores show that, overall,
forecasters at Albany generally are have greater errors than the FWC guidance,
and even greater errors than the MAV guidance at GFL and POU. Fifth period
temperature verification scores for all three stations show that the MAV MOS
guidance ranges from 10 to 50 percent better than Albany forecasters.
John S. Quinlan
NOAA/NWS, Weather Forecast Office, Albany, New York
Richard J. Westergard
NOAA/NWS, Weather Forecast Office, Albany, New York
Jann M. Joyce
Hotel & Travel Coordination, Review of Publications
Kenneth D. LaPenta
Web Page Support
Vasil T. Koleci
Northeast Regional Operational Workshop Preprint Cover Design
Warren R. Snyder
Northeast Regional Operational Workshop Coordinator
Center for Environmental Science and Technology Management
Conference Facilities
National Weather Service Eastern Region
Preprints
Capital Region of New York Chapter of American Meteorology
Society
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